Chapter 2.2 Study Guide
THE CHEMISTRY OF FOOD
PLTW – PBS
Food Testing Lab
 Know the chemical tests used to detect each
substance
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Glucose – Use Benedict’s solution, heated, green/yellow is
positive, stays blue is negative
Starch – Use Iodine, if turns black is positive, if stays
brown/amber it’s negative
Protein – Use Biuret Stain, if turns pinkish/purple it’s positive,
if stays a bluish-clear then negative
Lipids – Use the brown paper towel test, if it leaves a clearish
oil spot then it’s positive, if the liquid dries then it’s negative.
Food Testing Lab
 Know the description and role for each of the
molecules we tested
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Starches – are complex carbohydrates which are a source of
energy
Glucose – is a simple carbohydrate which is a source of energy
Protein – Critical for building tissues, fighting disease
(immunity), and facilitating chemical reactions
Lipids – such as fats and oils, they help in cell membrane
production and hormone production
Food Testing Lab
 Be able to discuss the role of Anna’s last meal (heavy
in starches and lipids) and how it could have
contributed to her death as a type 1 diabetic.
 Describe the role of using water during the initial
testing of the indicators.
 Describe the purpose of doing the part 1 of the lab
(testing known solutions against water) prior to
doing the actual testing of the foods.
Food Labels
 Be able to discuss the definition and importance of
EACH of the nutritional terms on your nutritional
terms chart. (see activity 2.2.2)
 Be able to analyze a food label for content as well as
health levels. Make sure to know recommended
values so you can determine if a particular ingredient
is too high or too low.
 Describe key features of a HEALTHY diabetic diet.
How does this relate to Anna Garcia???
 Explain the reasons for limiting things such as
saturated fat, cholesterol, and sodium.
Biochemistry of Life
PLEASE REVIEW THE 2.2.3 CHEMLIFE POWERPOINT
FROM THE LMS. THE MATERIAL PRESENTED IN
THIS POWERPOINT WILL BE COVERED
EXTENSIVELY ON THE TEST. YOU ALSO SHOULD
HAVE NOTES OVER THE POWERPOINT FROM WHEN
IT WAS COVERED IN CLASS.
USE THESE HELPFUL VIDEOS ALSO:
BIOLOGICAL MOLECULES
MOLECULES OF LIFE
ATOMS & THE PERIODIC TABLE
CHEMICAL BONDS
Dehydration vs. Hydrolysis Reactions
 Dehydration synthesis – when larger molecules are form by
connected smaller molecules. During this process an -H and
–OH are removed from the smaller molecules so they have an
opening to connect. Thus the H, OH will combine together
forming water (H2O). Thus, Dehydration synthesis is the
creating of larger molecules by the removal of water.
 Hydrolysis Reactions – When larger molecules need to be
broken down into smaller molecules, water will break the
bonds between the two molecules and attach to the open
spaces. Thus, hydrolysis reactions is the process of using
water to break down larger molecules into smaller molecules.
 http://education-portal.com/academy/lesson/hydrolysisdehydration-and-ionic-reactions-definitionsexamples.html#lesson
Chemical Bonds and Energy
 What is the relationship between chemical bonds
and energy?
 Explain how the body gets the energy it needs to
function from the food we eat.
 Compare and contrast saturated and unsaturated
fatty acids
 Which would give you more energy:
monosaccharide, disaccharide, or a
polysaccharide?
Energy in Food
 Energy from carbohydrates is released in the cells
through a process called cellular respiration. The
energy produced is called ATP (Adenosine
Triphosphate)
 calorie – the amount of energy needed to raise the
temperature of 1kg of water 1°C (this is a chemistry
calorie)
 Calorie – food calories (actually is 1000 calories)
 Energy in food is found by burning the food to heat
water and measuring the increasing in temperature
of the water – known as calorimetry